[1] We present new polarimetric radar data for the surface of the north pole of the Moon acquired with the Mini-SAR experiment onboard India's Chandrayaan-1 spacecraft. Between mid-February and mid-April, 2009, Mini-SAR mapped more than 95% of the areas polewards of 80°latitude at a resolution of 150 meters. The north polar region displays backscatter properties typical for the Moon, with circular polarization ratio (CPR) values in the range of 0.1-0.3, increasing to over 1.0 for young primary impact craters. These higher CPR values likely reflect surface roughness associated with these fresh features. In contrast, some craters in this region show elevated CPR in their interiors, but not exterior to their rims. Almost all of these features are in permanent sun shadow and correlate with proposed locations of polar ice modeled on the basis of Lunar Prospector neutron data. These relations are consistent with deposits of water ice in these craters.

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By__ :~stributi orq Aval abtlity Codes va 1.0 SCOPE 1.1 Identification Raytrace technique for a laterally heterogeneous environment. 1.2 Purpose Electromagnetic (EM) wave propagation is the transmission of an EM wave between a transmitter and a receiver. If a particular point on the wave front is followed over time, the collection of point positions would define a ray. The ray would coincide with a line from the transmitter to the receiver, as illustrated in figure 1.1-1. The purpose of this raytrace technique is to describe an EM wave's path in terms of rays, as the wave propagates through a laterally heterogeneous medium where the index of refraction is allowed to vary both vertically and horizontally.